The telephone and communications industry in the past has generally used electrical wires and cable installations in the transmission of telephone and other communications signals from one point to another. Due to the recent improvements in fiber optics technologies in the communications area, it has become economical and advantageous to use fiber optics elements to transmit telephone and other communications signals from one point to another. With the present fiber optics technology a fiber optics cable or element which is approximately the same size as a conventional wire element has the capacity to transmit many times the amount of information as the conventional wire element. Thus, the replacing of the conventional wiring system with fiber optics bundles of approximately the same size could greatly increase the capacity of the present communications system while utilizing the installation routes already in place.
It has been a recent goal of those in the art to utilize the fixtures, which are already in place in the existing communications systems, for replacement with fiber optics cables as the present communication lines reach their capacity.
At the present time there exists a system of underground conduits through which the conventional communication cables are routed to create the communication system presently in use. It is particularly desirable in these applications when substituting the conventional communication cables with the fiber optics elements or cables to use the existing conduits rather than attempting to replace the conduits, since replacement would be costly and require destructive excavations of roadway surfaces. Due to the increased capacity and decreased size of the fiber optic elements or cables it is desirable to place as many fiber optics elements or cables in a particular conduit as is possible. Thus the value of a particular conduit is directly related to the number of the fiber optics elements or cables which can be placed in a particular conduit.
Because of the nature of fiber optics cables in their use in the communications industry it is desirable to isolate particular bundles of fiber optics elements into discreet and independent chambers inside of an existing conduit. It is desirable to produce a configuration of a conduit liner which can be inserted into the existing conduit and would contain a series of discreet and independent chambers into which fiber optics elements could be inserted. Therefore a conduit liner which provides the greatest number of usable chambers in a particular conduit maximizes the value of the conduit regarding a fiber optics installation.
Attempts have been made to provide such inserts. However, it has been found that the use of an insert which has a series of integrally formed chambers creates problems in that the underground conduits used may have several curvatures or bends that must be traversed by such an insert. In the inserts of the past, the chambers have been made somewhat larger than the size of the fiber optics bundles desired to be inserted therein because while traversing these bends in the conduit the chambers have a tendency to become distorted and/or compressed to an out of round condition because of routing around these curves or bends in the conduit. In addition, the necessity for traversing these curves makes it harder to insert the liner into the existing conduit because of the forces required to distort the liner and the increased frictional forces between the liner and the conduit surfaces particularly at curvatures or bends in the conduit.
Because of these problems the liners of the past required an abnormally large space for the internal chambers which resulted in a decrease in the number of chambers which could be used for fiber optics cables in a particular conduit installation. In addition, the frictional engagement of the conduit walls and the distortion in liners of the past, even though relatively flexible materials were used, decreased the distance that a particular liner could be pulled through a conduit thereby requiring a greater number of splices in the liner and requiring more man hours and an increased number of access points for pulling a particular liner through an existing conduit, or alternatively the use of thicker walls of the liner tubes was required which reduces the number of tubes which may be pulled into a given conduit.